Regional expression of sulfatides in rat kidney: immunohistochemical staining by use of monospecific polyclonal antibodies.

Sulfatides are quantitatively prominent glycosphingolipids of rat kidney. In order to gain insight into their possible physiological significance in this organ, and their possible role in Heymann's nephritis, the main sulfatide components were localized immunohistochemically. The antibodies used recognized the sulfatides Sgal1, Stri1, Stri2, and Stet2a. Stri1 epitopes were expressed in the brush border of proximal tubuli, whereas Stri2-specific immuno staining was observed in cortical and medullar collecting ducts. Both Stri1 and Stri2 were also expressed by interstitial cells of the inner medulla. Stet2a was visualized in epithelia of the distal tubules of Henle's loop and the juxtaglomerular apparatus, including the macula densa. The mAb Sulph-I, that recognizes the SO3(-)-3Galbeta<epitope of Sgal1, seminolipid, and Slac1, prominently stained the cortical and medullar collecting ducts. No sulfatide was immuno-stained in the glomerular region. For this reason, the possibility of a direct involvement of anti-Stri1 and Stri2 antibodies in the etiology of Heymann's nephritis appears to be less likely. A strict correlation between the local sulfatide content, as analyzed by chemical estimation, and the sulfatide expression, as observed by immunohistochemical methods, may not be possible.